There probably isn't enough money in the world -- or time -- to label everything that we produce and consume with accurate carbon footprints. More importantly, consumers haven't asked for it. The most common consumer response to these labels is confusion, followed perhaps by irritation at having to look at one more number when they're simply trying to grab that gallon of milk and be on their way.

This doesn't mean that carbon (or other) footprinting is dead. But it does mean that the exercise of footprinting products and organizations needs to be rethought. The question is, what can we really do with the carbon footprint metric?

We know that the carbon footprint tracked over time is not only a good indicator of energy use -- including reliance on fossil energy and transition to renewables -- but also of energy and material efficiencies, waste reduction, land use and other resource uses. It is hard to compress all of this into a single number, so the carbon footprint is never going to be a perfect measure of environmental impact.

There is, in fact, an excellent analogy with another widely used single metric, and that is time. Lean processes -- ubiquitous now in many economic sectors -- are based on the premise that compressing time reveals hidden quality problems and that their resolution leads to more efficient, cost-effective business processes. Now, time is not a perfect measure of quality either, but it works reasonably well not only in manufacturing but also in service industries [PDF]. Lean has been successful because it is always easier to understand and optimize one variable -- in one dimension -- rather than multiple variables that may or may not be correlated.

Lean processes can be green as well in many cases, but that is not necessarily true [PDF] in general. After all, they haven't been optimized explicitly for low environmental impact. That is really where carbon comes in. Analogous to the use of time in lean processes, carbon can be the single variable to optimize in what we might call clean processes (what I really mean, of course, is cleaner processes).

Note also that lean service processes -- such as health care delivery or auto repair [PDF] -- may require some modest changes in consumer behavior, but these are usually not painful changes. Consumers are often delighted by the changes, which involve same-day appointments, minimal waiting (compressing time!), and highly streamlined operations. In the same spirit, successful clean processes cannot impose additional burdens on consumers -- and that includes comparing carbon footprint labels. It is also inefficient to leave all the optimization to consumers, who can only choose between finished products or choose to consume less of something.

If there is an opportunity to take carbon out of a product, it should happen before the product (or service) makes contact with consumers. This means higher efficiencies, lower waste, better choice of raw materials, and ultimately cleaner products and processes that are fully optimized for carbon. The business case for doing this would be to reduce the cost of production and delivery of anything, while providing a more pleasing experience to consumers.

There may well be additional reasons for carbon footprinting, such as reporting and transparency requirements. But these often get entangled in incomplete analyses and partial disclosures where the aim is to shore up a corporation's green credentials. To take the time and care needed to do the footprinting right, companies need more compelling primary reasons.

Nothing is more compelling than an improved bottom line and potentially happier consumers.

Kumar Venkat is president and chief technologist at CleanMetrics Corp., a provider of analytical solutions for the sustainable economy.